Potential participants completed the Health and Habits Survey, which contained questions about diet, smoking, exercise, stress, and usual drinking, and the T-ACE, a 4-item alcohol-screening instrument. The Health and Habits Survey was given to patients initiating prenatal care at 1 of 3 obstetric practices (clinic, faculty, or private group affiliate) of the Brigham and Women’s Hospital in Boston, Massachusetts. E-mail and other study announcements also invited study inquiries, and the screening survey was made available at the time of inquiry.
Research assistants evaluated potential participants for 4 inclusion criteria. The first criterion was a positive T-ACE, with a total score of 2 or more. The T-ACE asks 4 questions that give the assessment its name: T, how many drinks does it take to make you feel high? (Tolerance); A, have people ever annoyed you by criticizing your drinking? (Annoyed); C, have you ever felt you ought to cut down on your drinking (Cut down); and E, have you ever had a drink first thing in the morning to steady your nerves or get rid of a hangover (Eye-opener). The tolerance question is given 2 points if the respondent reports needing more than 2 drinks, and affirmative replies to the A, C, and E questions are each given one point. The second criterion was being at risk for prenatal alcohol use, which was defined as any alcohol consumption in the 3 months before study enrollment (while pregnant), or consumption of at least one drink per day in the 6 months before study enrollment, or drinking during a previous pregnancy. The third criterion was gestation less than 28 weeks and intention to carry pregnancy to term. The fourth criterion was agreement to study terms, which included randomization to treatment by computer assignment, postpartum follow-up interview, selection of a partner who would participate in a diagnostic interview, the brief intervention if so randomized, and postpartum interview. Subjects were informed of their treatment assignment at the time of study enrollment, before the diagnostic interview.
Study exclusion criteria were 1) current treatment for alcohol or drug abuse, or substance abuse–related medical illness, 2) current physical dependence on alcohol requiring medically supervised detoxification, 3) current use of opiates, cocaine, or other illicit substances, 4) inability to complete study questionnaires, and 5) intention to terminate pregnancy before term gestation.
Sample size calculations for the trial were based on 95% confidence level (α = 0.05), 90% power, 1:1 ratio of treatment to control subjects, and the expectation that 50% of the control group would become abstinent, based on the spontaneous rate of abstinence reported for pregnant women.18
The rate of abstinence in the brief intervention group was estimated to be 70%, based on the rate reported from a previous study of brief intervention for prenatal alcohol use.19
Thus, the total number of subjects needed would be 268, without attrition, and 295, with 10% attrition. Our goal was to enroll 300 subjects.
At the diagnostic interview given by research assistants, pregnant participants completed the 1) Alcohol Timeline Followback, to obtain estimates of their daily drinking for the 6 months before study enrollment;20
2) Alcohol Abstinence Self-Efficacy scale, to measure their evaluations of their perceived temptation to drink and their efficacy to abstain in 20 common situations;21
and 3) Healthy Pregnancy Facts, a series of 7 statements about healthy habits during pregnancy that the respondent was asked to judge as true or false, among other instruments.
Separately, the partners met with research assistants to complete 1) the Health and Habits Survey, already described; 2) National Institute on Alcohol Abuse and Alcoholism quantity-frequency questions, 9 questions about personal use of beer, wine, whiskey, gin, or other spirits in the previous 30 days;22
3) collateral report, the National Institute on Alcohol Abuse and Alcoholism quantity-frequency questions about the partner’s alcohol use in the past 90 days; and 4) Healthy Pregnancy Facts, a series of 7 statements about healthy habits during pregnancy that the respondent was asked to judge as true or false.
The brief intervention was then given to the randomly assigned couple by 1 of 2 nurse practitioners or the principal investigator according to the following structure: 1) knowledge assessment with feedback, 2) contracting and goal setting, 3) behavioral modification, and 4) summary. The single-session brief intervention was selected because of its efficiency and prior history of success, but was enhanced in this study by including the partner.19
The interventionists, all experienced clinicians with at least a master’s degree, were trained and directly observed in the delivery of the brief intervention. Their brief intervention summaries and other notes were continuously reviewed for treatment consistency. Each intervention took an average of 25 minutes to complete. Brief interventions were not audio taped because of concerns about participant acceptability.
Knowledge assessment with feedback1
began with a review of the Healthy Pregnancy Facts knowledge measure completed by both the subject and her partner. Questions were answered and any misapprehensions were discussed. The subject’s actual alcohol consumption was not discussed in the presence of her partner, unless she volunteered the information. In the next step of goal setting and contracting,2
the subject was asked to describe her prenatal drinking goal (eg, abstinence), and the rationale for her choice was explored. The couple was informed that maternal abstinence from alcohol was the most prudent choice during pregnancy. They were asked if either the subject or the couple had made any lifestyle changes because of her pregnancy (eg, work schedule). The behavioral modification3
portion consisted of asking the subject to identify situations or circumstances when she might be tempted to drink alcohol (eg, at a wedding) and to then list some alternative behaviors (eg, having some food instead). The partner was asked to describe ways in which he or she had modified or made plans to change behaviors that could offer support to the pregnant woman, such as drinking less, socializing differently, or doing more at home. The content of the brief intervention was summarized4
on a no-carbon-required form, and the couple was given the original summary. The brief intervention was timed and the interventionist was asked to record any relevant impressions on a separate sheet after the intervention, in addition to the summary form.
At the postpartum follow-up interview, subjects completed the 1) Alcohol Timeline Followback for alcohol consumption from the time of study enrollment until delivery, and 2) Alcohol Abstinence Self-Efficacy scale, already described. At the postpartum interview, partners provided 1) a collateral report on the subject’s use of alcohol since study enrollment using the National Institute on Alcohol Abuse and Alcoholism quantity-frequency questions, 2) follow-up Health and Habits Survey, to assess changes in health habits by the partner since enrollment, and 3) National Institute on Alcohol Abuse and Alcoholism quantity-frequency questions about personal consumption of beer, wine, whiskey, gin, or other spirits since study enrollment. Whenever possible, the subjects and partners completed the follow-up interviews with research assistants who did not administer their diagnostic interviews.
Subjects who completed the diagnostic interview (control) or diagnostic interview with brief intervention (treatment) received an honorarium of $50.00 and $100.00 for the postpartum interview. Support partners received an honorarium of $25.00 for each of the diagnostic and postpartum interviews.
This study was reviewed and approved by the Institutional Review Board of the Brigham and Women’s Hospital. In addition, a Certificate of Confidentiality for the project was granted by the Department of Health and Human Services.
Data were analyzed using univariate and multivariable techniques to compare the treatment (brief intervention) and control (diagnostic interview only) groups before and after study enrollment with SAS 8.2 (SAS Institute, Cary, NC). Descriptive results are reported as percentages and means. Baseline patient demographic and behavioral characteristics were compared between the 2 study arms using Wilcoxon or Fisher exact tests.
Ordinary least-squares regression models were used to evaluate the effect of the brief intervention on 3 dependent variables: drinks per drinking day (quantity), percentage of drinking days (frequency), and a combined quantity-frequency measure subsequent to study enrollment. To control confounding and reduce variability, all regression models included demographic variables, history of prior drinking, temptation and confidence in managing temptation to drink in a variety of circumstances, use of cigarettes, and high-risk pregnancy status, in addition to the primary predictor indicating treatment or control status. The first model was an intent-to-treat analysis of all 304 subjects. The second model added an interaction term between treatment status and alcohol use at enrollment to the first model to investigate whether women with the more severe drinking problems might benefit the most from the intervention.23
The third model was a brief intervention efficacy analysis that specifically examined the impact of the support partner’s participation in the treatment. Multiple imputation, with 5 imputations, was used to manage missing data.24
All analyses were replicated with mean substitution to verify the findings from the multiple imputation.